1. Technical Field
The present invention is directed to an improved method and system for increasing network capacity in a Global System for Mobile Communications (hereinafter GSM) networks and in particular for overall system capacity improvement by reducing the number of visitor location register queries. Still more particularly the present invention relates to an improved method and system for determining when to forward calls to a visiting mobile switching center when a subscriber has detached from the GSM network.
2. Description of the Related Art
In telecommunications, based on a Global System for Mobile Communications xe2x80x9cGSMxe2x80x9d standard, a land-to-mobile phone call consists of two-phases; a setup phase and a user communication phase. During the call setup phase, signaling messages are exchanged between a mobile terminal and a network through a dedicated signaling channel. Currently, the land-to-mobile GSM call setup procedure requires the interrogation every time by a gateway mobile switching center GMSC to a remote home location register (referred to as HLR) and then to a visitor location register (referred to as VLR) located at a visiting mobile switching center for the network to set up a call to the mobile terminal. Having to continuously interrogate the HLR and visiting mobile switching center (hereinafter the VMSC) when a subscriber has detached from the GSM network results in significant processing overhead at the HLR and VMSC. This increases the signaling traffic load, as well as call setup delay.
Therefore, a need exists to increase network efficiency and improve the grade of service by reducing the HLR/VMSC signal-processing load. Capacity improvement can be obtained by reducing the number of HLR/VLR queries. In view of the above, it should be apparent that a method and system that allows the processing of calls without HLR and VLR queries when a subscriber has detached would be highly desirable. The present invention solves this problem in a new and unique manner that has not been part of the art previously.
It is therefore one object of the present invention to provide an improved method for call setups for GSM networks and in particular for overall system capacity improvement in GSM networks by reducing the number of home location register and visitor location register queries.
It is another object of the present invention to provide a method which reduces the processing requirement at the home location register and the visiting mobile switching centers due to the removal of some of the send routing information and provide roaming number messages.
It is yet another object of the present invention to provide an improved method that determines the routing of calls from gateway mobile switching center to a forwarding number when the subscriber has detached from the network.
The foregoing objects are achieved as is now described. A method and system for improving overall system capacity in GSM networks by reducing the number of visitor location register queries is disclosed. The method and system determines if processing subsequent calls for a mobile terminal which has been detached by its subscriber from the GSM network should involve its visiting mobile switching center based on the call arrival characteristics of the subscriber. A xe2x80x9ccall-arrival-after detachxe2x80x9d counter is created at the home location register and visitor location register for tracking the number of incoming calls that occur during the interval when the subscriber has detached. The value of this counter is compared for every incoming call to a threshold level value for determining how the call is to be processed. The threshold level value is determined based on the past call arrival characteristics of the subscriber. The method and system of the present invention makes it unnecessary to query the VLR and HLR when a land-to-mobile call arrives for a subscriber and the subscriber has detached from the network thereby increasing network capacity while reducing processing load.
The above as well as additional objects, features, and advantages of the present invention will become apparent in the following detailed written description.